Editor’s note: This week and next, we’re presenting a 5-part series of excerpts from Peter Calthorpe’s book, “Urbanism in the Age of Climate Change.” This is installment number two. Thanks to Island Press, a few lucky Streetsblog readers will be selected to receive a free copy of the book. To enter the contest, fill out this form.
California’s effort to implement its new greenhouse gas reduction laws has provided a comprehensive look at urbanism and its potential in relation to a range of conservation and clean energy policies. The Vision California study, developed for the California High Speed Rail Authority and the California Strategic Growth Council, measured the results of several statewide land use futures coupled with conservation policies through the year 2050.5 The results make concrete the choices before us, the feedback loops, and the scale of both benefits and costs.
California is projected to grow by 7 million new households and 20 million people, to a population of nearly 60 million, by 2050.6 It is currently the eighth-largest economy in the world and therefore provides an important model of what is possible. The study compared a “Trend” future dominated by the state’s now typical low-density suburban growth and conservative conservation policies to a “Green Urban” alternative. This Green Urban alternative assumed that 35 percent of growth would be urban infill; 55 percent would be formed from a more compact, mixed-use, and walkable form of suburban expansion; and only 10 percent would be standard low-density development. In addition, the Green Urban alternative would push the auto fleet to an average 55 miles per gallon (MPG), its fuel would contain one third less carbon, and all new buildings would be 80 percent more efficient than today’s norm. It does not represent a green utopia, but it is heading in that direction. The results of this comparison highlight just how much is at stake and what the costs will be.
Remarkably, the quantity of land needed to accommodate the next two generations was reduced 67 percent by the Green Urban scenario, from more than 5,600 square miles in the Trend future to only 1,850 square miles. By comparison, the state’s current developed area is 5,300 square miles.7 This difference would save vast areas (up to 900 square miles) of farmland in the Central Valley along with key open space and habitat in the coastal regions of the state. The more compact future means smaller yards to irrigate and fewer parking lots to landscape, saving an average of 3.4 million acre-feet of water per year—enough to fill the San Francisco Bay annually or to irrigate 5 million acres of farmland.8 Less developed land also translates to fewer miles of infrastructure to build and maintain. The annual savings would be around $194 billion for the state, or $24,300 for each new household—not including the costs of ongoing maintenance. In addition, the Trend future would cost more in police and fire services as coverage areas increase.